Studio UI: Remove Add Plugin button from left panel

Details

Moved the "add plugin" behavior from a plugin's left panel to an "Add Entity" button in the CDAP Studio UI.

Rank:

1|hzy0wv:

Description

Remove the Add Plugin button on the left panel of the Pipeline Studio view, as this is replaced by the Add Entity button, also present in the studio. Also, move the import button next to the export button.